To Identify the Dangerous Length of External Laryngeal Nerve In Relation to Thyroid Pole In Cadaveric Thyroid Glands

ABSTRACT

Introduction: The external laryngeal nerve passes through the “space of Reeve” cricothyroid space. It has also been described as lying in the Joll’s triangle. It is often inadvertently neglected during thyroid surgeries. It has been named after a singer who lost her voice after a thyroid surgery, as the “nerve of Galli Curci” Aim: To identify the dangerous length of the external laryngeal nerve in relation to the thyroid pole. Material and Methods: Fifty laryngeal nerves were dissected using conventional method of dissection, in twentyfive embalmed cadavers used for teaching purpose at Karpaga Vinayaga Institute of Medical Sciences and Research, Madurantakam. The observations were noted and photographs taken. The course and relations were carefully noted. Results: 38 specimens (76%) had the superior laryngeal nerve measuring 4cm. in 8 specimens (16%) it was 3.5 cm and in 04 specimens (8%) it measured 3.8 cm. It was observed that the external laryngeal nerve crossed the superior thyroid pole at less than 1cm only in three (6%) of the fifty nerves. Conclusions: The critical length of the nerve would be dangerous if the nerve crosses the superior thyroid pedicle close to thyroid pole at less than 1 cm. The consequences of neglecting the critical length would injure the nerve and cause dysphonia or raspy voice.